From: Stefano Crocco <stefano.crocco@...>
Date: 2009-11-24T20:03:13+09:00
Subject: Re: Warning: instance variable @foo not initialized

On Tuesday 24 November 2009, Seebs wrote:
> |On 2009-11-24, Stefano Crocco <stefano.crocco@alice.it> wrote:
> |> If the warnings only annoy you, you should be able to disable them by
> |> not passing the -w option to ruby. If instead you're worried that they
> |> can mean there's something wrong, I think you don't need to. Most of the
> |> times, warnings issued by ruby are harmless.
> |
> |There's two issues.
> |
> |1.  Actually, those warnings happen even without -w.  (Unless there's
> |something non-obvious passing the -w to Ruby that I didn't think about.)
> |2.  I actually really DO want -w warnings for my code.  Is there a way to
> |do a require that suppresses warnings during parsing of the required code?
> |
> |-s
> |

I never used Prawn, so I can't tell why it issues warnings even without the -w 
option. However, you can control this setting from inside your code using the 
$VERBOSE global variable. It is initially set by ruby to one of the following 
values:
* true if the -w, -v or --verbose flags have been passed on the command line
* nil if the -W0 flag has been passed on the command line
* false if none of the above flags has been given

You can change it from inside your code to avoid warnings from Prawn:

#your code
...
old_verbose = $VERBOSE
$VERBOSE = nil
#code which makes prawn issue warnings
...
$VERBOSE = old_verbose

Stefano